1. Field of the Invention
The present invention relates to a recording and/or reading device with magnetic heads arranged notably in matrix form.
This device is designed to be mounted, for example, in magnetic recorders such as those used in computers or in on-board equipment or else in video recorders and tape recorders for professional use as well as for large-scale consumer applications.
A magnetic head is formed by a magnetic circuit, with a gap, associated with at least one conductor to which there is applied the signal to be recorded on a medium positioned in the vicinity of the gap. This signal creates a magnetic field in the magnetic circuit and this is used to magnetize a small portion of the medium that is in a position facing the gap.
2. Description of the Prior Art
For the recording and reading of information elements, it is increasingly being sought to miniaturize recording/reading heads so as to increase the density of information elements on a recording medium. For this purpose, it has been necessary to make heads in thin layers or thin films.
It is also sought to associate several magnetic heads so as to get rid of the movements of the head. This enables also an increase in the speed of writing of information elements on the medium. This has led to the grouping of several heads in rows or even in matrix form.
The patent FR 2 630 853 describes a matrix device with magnetic heads made in thin layers.
This device is formed by a grooved magnetic substrate with pads arranged in rows and columns. Row conductors and column conductors are positioned in the grooves and covered and/or embedded in a non-magnetic material. A first magnetic layer is deposited on one in every two columns of pads. This layer is designed to form the first poles of each magnetic head. On this first magnetic layer and on the rest of the substrate, a layer of a non-magnetic material is deposited. This layer includes a flank of the first layer. This non-magnetic layer is designed to form the gaps of the magnetic heads. Then, on the layer of non-magnetic material, a second layer of magnetic material is deposited. This second layer is designed to form the second poles of the magnetic heads.
It surmounts the pads that are not covered by the first magnetic layer. A machining operation, a polishing operation and a cutting operation enable the poles to be made flush and makes it possible to demarcate them as well as the gaps.
A non-magnetic link is made beneath the second formed poles. It connects the gaps of two heads located in neighboring columns.
In this type of device, two magnetic heads located in neighboring columns do not have identical performance characteristics during a recording caused by one and the same flux for two linked gaps are symmetrical.
This difference in performance characteristics is further increased when the gap, instead of being perpendicular to the surface of the substrate, is now tilted.
A pole whose upper surface forms an acute angle with the gap starts getting saturated for a lower intensity of flux than does a pole whose upper surface forms an obtuse angle with the gap.